Minimising discards while taking revenue into account : spatio-temporal assessment of catches in an artisanal shrimp trawl fishery in Peru

Funding: Newton Fund (414695818); University of St Andrews Impact and Innovation 2021; Fondo Nacional de Desarrollo Científico Tecno 2018-222.Around 4.2 million tonnes of fish and other species, some of which are of conservation concern, are discarded every year in bottom trawl fisheries. This study focusses on a small-scale shrimp trawl fishery located in northern Peru that operates with high level of discards which causes conflict with other local fishers. Despite trawling being an illegal activity within the 5NM off the coast, this fishery has been operating in these inshore areas for over 40 years because it sustains the well-being of hundreds of fishers. This study aimed to identify the factors that affect the spatio-temporal variation in catches in order to propose recommendations that can be adopted by fishers to minimise their impact on the ecosystem while still providing economic opportunities. The spatial distributions of shrimp, main commercial species and discards were modelled over time using hierarchical generalised additive models. Strong spatio-temporal variation was observed for all catch components and moon phase affected commercial species and discards differently. The results show that, to reduce the environmental impacts of this fishery in the short-term, the fishing area could be divided into north and south and that fishing activities should be limited to the southern area in the autumn. Other recommendations rely on temporal closures during the week of the first quarter of the moon phase. Finally, considering the institutional weaknesses in monitoring, control and surveillance, we suggest that the only realistic approach to reduce the fishery's environmental impacts in the short-term is to foster the willingness of fishers to adopt responsible fishing practices. Yet, long-term solutions will require comprehensive co-management efforts.Publisher PDFPeer reviewe

Estimating energetic intake for marine mammal bioenergetic models

This work was primarily funded under an award from Office of Naval Research: N000142012392, and with support from the Marine Mammal Commission project: “A priority setting exercise to identify key unanswered questions in marine mammal bioenergetics”. Funding from the Joint Nature Conservation Committee supported fish energy analyses - award C180241-1285.Bioenergetics is the study of how animals achieve energetic balance. Energetic balance results from the energetic expenditure of an individual and the energy they extract from their environment. Ingested energy depends on several extrinsic (e.g prey species, nutritional value and composition, prey density and availability) and intrinsic factors (e.g. foraging effort, success at catching prey, digestive processes and associated energy losses, and digestive capacity). While the focus in bioenergetic modelling is often on the energetic costs an animal incurs, the robust estimation of an individual’s energy intake is equally critical for producing meaningful predictions. Here, we review the components and processes that affect energy intake from ingested gross energy to biologically useful net energy (NE). The current state of knowledge of each parameter is reviewed, shedding light on research gaps to advance this field. The review highlighted that the foraging behaviour of many marine mammals is relatively well studied via biologging tags, with estimates of success rate typically assumed for most species. However, actual prey capture success rates are often only assumed, although we note studies that provide approaches for its estimation using current techniques. A comprehensive collation of the nutritional content of marine mammal prey species revealed a robust foundation from which prey quality (comprising prey species, size and energy density) can be assessed, though data remain unavailable for many prey species. Empirical information on various energy losses following ingestion of prey was unbalanced among marine mammal species, with considerably more literature available for pinnipeds. An increased understanding and accurate estimate of each of the components that comprise a species NE intake are an integral part of bioenergetics. Such models provide a key tool to investigate the effects of disturbance on marine mammals at an individual and population level and to support effective conservation and management.Publisher PDFPeer reviewe

Assessing discards in an illegal small-scale fishery using fisher-led reporting

Funding: Newton Fund (IL 2018-Grant Agreement 414695818 James PER), Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (PE) (FONDECYT 2018-222).About a third of all marine fish in the world are caught in Small-Scale Fisheries (SSF). SSF are increasingly recognised as essential for food security and livelihoods for vulnerable and economically fragile communities globally. Although individual SSF vessels are usually perceived as having little impact on the ecosystem, the cumulative impact of gear type and number of vessels may be substantial. Bottom trawling is a common fishing method that can greatly influence the marine ecosystem by damaging the seafloor and generating high levels of discards. However, appropriate sampling coverage using on-board observer programmes to collect these data from SSF are rare, as they are expensive and pose logistical constraints. A mobile App was used to assess whether self-reporting by fishers could provide reliable fine-scale information on fishing effort and discards over time in an illegal shrimp trawling fishery in northern Peru. Maps depicting the spatial distribution of trawling effort and the proportion of discards from observers and fishers were compared using the Similarity in Means (SIM) Index, which ranges from 0 when spatial patterns differ completely to 1 when spatial patterns are very similar. High levels of agreement between spatio-temporal patterns of effort (SIM Index = 0.81) and discards (0.96) were found between fisher and observer maps. Moreover, far greater spatial coverage was accomplished by fishers, suggesting that self-reporting via an App represents a useful approach to collect reliable fisheries data as an initial step for effective monitoring and management of these fisheries.Publisher PDFPeer reviewe

Working Group on Marine Mammal Ecology (WGMME)

162 pages.-- This work is licensed under the Creative Commons Attribution 4.0 International Licence (CC BY 4.0)The Working Group on Marine Mammal Ecology met in 2021 to address new information on marine mammal ecology relevant to management. Two terms of references were standing ToRs; under the first of these, ToR A, new and updated information on seal and cetacean population abundance, population/stock structure, manage-ment frameworks as well as anthropogenic threats to individual health and population status were reviewed along with findings on threats to marine mammals such as bycatch, pollution, marine debris and noise. ToR B is a cooperation with WGBIODIV to review species-specific for-aging distributions (considering horizontal and vertical dimensions depending on data availa-bility) and to estimate consumption by marine mammal species representative in case study ar-eas. ToR C was implemented to review aspects of marine mammal fishery interactions not cov-ered by ICES WGBYC. ToR D is the second standing ToR and concerns updating the WGMME seal database, which was updated with the latest dataN

Report of the ICES Working Group on Marine Mammal Ecology (WGMME)

131 pages.-- This work is licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0)Five terms of reference (ToRs) were addressed at the working group. The first three terms of reference were standing ones. Under ToR A, new information on cetacean and seal population abundance, distribution, and population/stock structure, was reviewed, including information on vagrancy in cetacean and pinniped species. For cetaceans, coverage from the latest SCANS-IV survey (summer 2022) was presented as well as the results of recent regional/national surveys, particularly those in the Bay of Biscay and around the Iberian Peninsula. Updates on population estimates and distribution were provided for particular species studies, such as some coastal bottlenose dolphin populations. For seals, latest monitoring results were given for harbour, grey, and Baltic and Saimaa ringed seals. In addition, where possible, local long-term trends were illustrated for those species, based on earlier efforts by WGMME to assemble these data into a seal database. For both species’ groups, recent records of vagrant species were summarised. Under ToR B, cetacean and seal management frameworks in the North Atlantic were discussed, with an overview of the EU Maritime Spatial Planning Directive, and examples from the United Kingdom, Spain and the Faroe Islands of national management frameworks regarding marine mammals.ToR C provided an overview of new published information with regards to anthropogenic threats to marine mammal populations following on from the review by WGMME in 2015 (ICES, 2015) and subsequent updates. These were considered under the following headings: cumulative effects, fishery interactions, chemical pollution including marine debris, underwater noise, ship strikes and other physical trauma, tourism disturbance, climate change, and new pathogens (including avian influenza). ToR D focused upon bycatch. In support of WGBYC, this ToR aimed to contribute to the Roadmap for ICES PETS bycatch advice. ToR E involved liaison with other WGs. The Chairs of the newly-formed WGJCDP introduced to WGMME members, the Joint Cetacean Database Programme, which is to be hosted by the ICES Data Centre. The scope to collect information on other marine species besides cetaceans was discussed. A meeting with another newly formed ICES working group, on Marine Protected Areas, was planned but was deferred at the request of that group. On behalf of the working group, the Chairs would like to thank The Swedish Museum of Natural History for hosting the meetingN

Marine mammal predator-prey interactions in the North Sea

Trophic levels within an ecosystem are linked by the functional response which describes how the consumption rate of a predator varies in relation to prey density. Knowledge of functional responses is key to understanding predator-prey interactions, population dynamics, predation pressure, prey preference, and the ecosystem. This thesis explores multi-species functional responses (MSFR) of key marine mammal predators in the North Sea, and the prey energy available to them. Spatiotemporal variation in prey energy available to harbour porpoises (Phocoena phocoena) was modelled, using species distribution models, and showed that large amounts of energy were available both within and outside the Southern North Sea (SAC). Sandeels are energy-rich, their patchy restricted distribution drove the observed patterns of the spatiotemporal distribution of all porpoise prey energy. The MSFR of three predator species (harbour porpoise, grey (Halichoerus grypus) and harbour seal (Phoca vitulina)) were modelled using Bayesian methodology. Fitted responses indicated that all predators exhibit a type III functional response, and that sandeels are important and more strongly preferred by grey seals and harbour porpoise compared to harbour seals. They may be preferred as they are probably easy to catch due to their immobility and predictable occurrence, as inferred from their restricted modelled distribution. Harbour seals have more diverse diets than grey seals and seem to show a more sigmoidal response which may indicate a greater tendency to switch between prey types. Of the predators, harbour porpoise had the highest consumption estimates, mainly due to the larger number of animals in the area. Generally, marine mammal consumption was low compared to fisheries landings (≤ 20%). Overall, this thesis shows the benefit of MSFR modelling to improve ecological understanding of important marine predators and the results allow future integration of the MSFRs into ecosystem models to explore the consequences of predation on various fish stocks

Integrating disparate datasets to model the functional response of a marine predator : a case study of harbour porpoises in the southern North Sea

1. Quantifying consumption and prey choice for marine predator species is key to understanding their interaction with prey species, fisheries, and the ecosystem as a whole. However, parameterizing a functional response for large predators can be challenging because of the difficulty in obtaining the required data on predator diet and on the availability of multiple prey species. 2. This study modeled a multi-species functional response (MSFR) to describe the relationship between consumption by harbour porpoises (Phocoena phocoena) and the availability of multiple prey species in the southern North Sea. Bayesian methodology was employed to estimate MSFR parameters and to incorporate uncertainties in diet and prey availability estimates. Prey consumption was estimated from stomach content data from stranded harbour porpoises. Prey availability to harbour porpoises was estimated based on the spatial overlap between prey distributions, estimated from fish survey data, and porpoise foraging range in the days prior to stranding predicted from telemetry data. 3. Results indicated a preference for sandeels in the study area. Prey switching behavior (change in preference dependent on prey abundance) was confirmed by the favored type III functional response model. Variation in the size of the foraging range (estimated area where harbour porpoises could have foraged prior to stranding) did not alter the overall pattern of the results or conclusions. 4. Integrating datasets on prey consumption from strandings, predator foraging distribution using telemetry, and prey availability from fish surveys into the modeling approach provides a methodological framework that may be appropriate for fitting MSFRs for other predators.Publisher PDFPeer reviewe

SEAwise Report on consistency of existing targets and limits for indicators in an ecosystem context

The SEAwise project works to deliver a fully operational tool that will allow fishers, managers, and policy makers to easily apply Ecosystem Based Fisheries Management (EBFM) in their fisheries. This SEAwise report investigates the consistency of existing targets and limits from the Common Fisheries Policy (CFP) and the Marine Strategy Framework Directive (MSFD). Trade-offs between different objectives (ecological, economic, social), targets and limits are highlighted. A wide range of model types (from bio-economic to full ecosystem models) has been applied to various case study areas accross the North East Atlantic and Mediterranean. Although model predictions are by nature uncertain, this study provides important information on likely inconsistencies between existing targets and limits and trade-offs expected under ecosystem- based fisheries management (EBFM). The scenarios investigated include the current range of management applied in terms of the Maximum Sustainable Yield (MSY) concept (i.e. strict MSY approach vs. Pretty Good Yield (PGY) approach allowing sustainable deviations from single species point estimates). The landing obligation is a key aspect of current fisheries management and was fully considered, in particular for mixed demersal fisheries.Maintaining current fishing effort without further management measures was the least sustainable option in nearly all cases studies. This approach led to increased risk of stocks falling below critical biomass limits. Although the fishing effort adaptions needed is highly case specific, this indicates that further management measures are likely to be needed to ensure a sustainable exploitation of all stocks.Scenarios applying a strict MSY approach in combination with the landing obligation as upper limit with fisheries ending when the first stock reaches in most case studies led to the lowest fishing effort. This had positive effects on MSFD related indicators such as bycatch of Protected, Endangered and Threatened (PET) species, benthic impact and the Large Fish Indicator as well as global indicators such as CO emission or ecosystem-based indicators like catch per . However, this scenario often led to the lowest catches from mixed demersal fisheries due to strong choke effects because fleets had to stop when their first quota was exhausted. This reduces social indicators such as food security, employment and wages. In terms of economic performance, the gains and loses were highly case specific. Scenarios applying the Pretty Good Yield concept and allowing sustainable deviations from the point estimate when stocks are in a healthy state often outperformed the scenarios applying as strict upper limit. Such scenarios, applying a more flexible interpretation of the MSY concept, led to reduced fishing effort compared to the status quo effort, but relaxed choke situations in mixed demersal fisheries to some extent leading to higher gross profits and in some case studies also to higher catches. Hence, they may constitute a compromise between the need to attain social as well as ecological objectives. Whether the associated effort levels lead to conflicts with MSFD objectives must be analysed when more internationally agreed thresholds become available for e.g., bycatch of PET species or benthic impact.The majority of case studies exceeded suggested thresholds for the global ecosystem indicators catch per km or primary production even under scenarios with high effort reductions. This can be explained to some extent by the fact that these indices are mainly driven by pelagic and industrial fisheries not always part of the models applied. Nevertheless, it indicates potential conflicts with such more holistic ecosystem indicators in their current form.Additional trade-offs in terms of yield were identified within the food web if e.g., demersal piscivorous predators feed on small pelagic fish and both groups are fished. Further, in case studies where small-scale fisheries (SSF) play an important role (e.g., Eastern Ionian Sea) additional trade-offs became apparent as different scenarios led to different ratios between revenues from small scale fisheries and revenues from large-scale fisheries. This adds another level of complexity when such aspects need to be taken more into account in future fisheries management under EBFM.The modelling assumed current selectivities and catchabilities will be maintained in the future. Especially trade-offs arising from fleets having to stop fishing when their first quota is exhausted or when e.g., a threshold for bycatch of PET species is reached may be resolved by improving selectivities via technical measures (e.g., closed areas or innovative gears) in the future. Deliverable 6.8 in month 36 will test such scenarios. Furthermore, the list of indicators and their targets and limits will be updated based on research within and outside SEAwise. Predictive capability of models will be enhanced by incorporating improved biological and economic sub-models in relation to environmental change. Climate change scenarios will be run and new harvest control rules (HCRs), proposed by SEAwise, will be tested. Finally, consistent targets and limits will be proposed for implementing EBFM